A conventional high-voltage switching circuit includes a normally-on element and a normally-off element which are series-connected to each other and switches on/off by switching according the normally-off element between conductive and non-conductive states. However, when the normally-off element becomes non-conductive earlier than the normally-on element, an overvoltage may be applied to the normally-off element such that a current may leak through the normally-off element or the normally-off element may be broken down entirely.
A method which causes both of the normally-off element and the normally-on element to perform switching by driving both of the normally-off element and the normally-on element using a common driver has been considered. However, in this method, the switching speed of the entire switching circuit would be rate-limited by the parasitic capacitance of the normally-on element, and, as a result, the switching performance of the normally-off element, which is comparatively fast in switching speed, would not be fully achievable. Thus, it is difficult to provide a device that is fast in switching speed while also preventing current leakage or breaking down.